1. Field of the Invention
The present invention relates to a semiconductor device, a manufacturing method of a semiconductor device, and an RFID tag.
2. Description of the Related Art
In recent years, wireless chips which transmit and receive data wirelessly have been developed actively. The wireless chips which transmit and receive data are called an RFID (Radio Frequency Identification) tag, an RF tag, an RF chip, a wireless tag, a wireless processor, a wireless memory, an IC (Integrated Circuit) tag, an IC label, an electronic tag, an electronic chip, or the like. Wireless chips for practical use now are wireless chips using a silicon substrate, which are the mainstream.
The production cost is a problem when a wireless chip (hereinafter referred to as an RFID tag in this specification) which transmits and receives data wirelessly is put to practical use. The production cost is divided into two types. One is a cost of materials and the other is a processing cost.
The cost of materials can be solved by miniaturization of a production rule, adoption of low cost materials, or the like. On the other hand, a problem of the processing cost cannot be solved as easily as the cost of materials. This is because a flip chip mounting method is often used when an inlet (one in which an IC chip is connected to an antenna and sealed) for an RFID tag is formed. Here, a flip chip mounting method means a method in which each IC chip is picked up and mounted on a film substrate. In this specification, an IC chip is a package in which an integrated circuit is formed on a silicon substrate, over a glass substrate, or the like. In the case of using a flip chip mounting method, there is a problem in that a yield is reduced but a processing cost is increased when an IC is disposed due to the miniaturization of a production rule, that is, the miniaturization of an IC chip.
As one of methods for reducing the processing cost, FSA (Fluidic Self Assembly) techniques shown in Reference 1 (U.S. Pat. No. 6,417,025B1) and Reference 2 (PCT International Publication No. WO 2004/086289A2) are proposed. The FSA techniques are techniques in which a base having a depression and an IC chip which fit the shape and the size of the depression are used, and the IC chip is disposed on the base in a self-aligned manner in liquid to form an inlet.
Since one RFID tag has been formed using one IC chip including the aforementioned FSA techniques so far, there has been a problem in that versatility of an IC chip has been low. For example, in the case where a memory having a large capacity larger than a memory required for another application has been required in an application, a new IC chip has been formed only for changing a memory capacity even in the case where there had already been an IC chip satisfying another condition. That is, since the IC chip has been formed based on a dedicated design for each RFID tag, a new IC chip has been required to be designed in accordance with its function when an RFID tag having another function has been required. Therefore, the limited production of diversified products has been extremely difficult in terms of cost. In addition, it has been difficult to provide an RFID tag having a required function immediately because of the dedicated design.
When a defect has been generated by a wiring defect or the like, there has been no method capable of restoring an RFID tag easily. Therefore, when a defect has been generated in an RFID tag, there has been a problem in that a yield has been decreased because the defective tag has been discarded.